Garmin GTN 650 Pilot's Guide - Page 181

10 Terrain Foreword 10.1 Terrain Configurations Getting Started During power-up of the GTN 6XX, the terrain/obstacle database versions are Xpdr Ctrl displayed along with a disclaimer. At the same time, the Terrain system self-test begins. A failure message is issued if the terrain test fails. Com/Nav Garmin provides the following terrain awareness solutions within the GTN 6XX environment: FPL • Terrain Proxmity - This is the standard Terrain function and refers to the Direct-To display of the relative terrain elevations on the moving map. No aural alerts of any type are provided by a Terrain configuration. Proc • TAWS-B (Optional) - A system developed to meet the terrain alerting and ground proximity requirements for Class B TAWS systems as defined in Wpt Info TSO-C151b. Garmin's GTN 6XX Terrain Awareness and Warning System (TAWS-B) is an optional feature and is intended to provide the flight crew Map with both aural and visual alerts to aid in preventing inadvertent Controlled Traffic Flight Into Terrain (CFIT). NOTE: Obstacles are removed from the Terrain and TAWS pages at ranges Terrain greater than 10 NM. Weather 10.2 Terrain Proximity Nearest Garmin Terrain Proximity is a non-TSO-C151b-certified terrain awareness system provided as a standard feature of GTN 6XX to increase situational Music awareness and help reduce controlled flight into terrain (CFIT). Terrain may be displayed on the Map and Terrain pages. Utilities Terrain Proximity uses information provided from the GPS receiver to System provide a horizontal position and altitude. GPS altitude is derived from satellite measurements. GPS altitude is converted to a Mean Sea Level (MSL)-based Messages altitude (GSL altitude) and is used to determine Terrain alerts. GSL altitude accuracy is affected by factors such as satellite geometry, but it is not subject Symbols to variations in pressure and temperature that normally affect pressure altitude devices. GSL altitude does not require local altimeter settings to determine MSL Appendix altitude. Therefore, GPS altitude provides a highly accurate and reliable MSL altitude source to calculate terrain and obstacle alerts. Index 190-01004-03 Rev. B Garmin GTN 625/635/650 Pilot's Guide 10-1